The control system of a power train comprising an internal combustion engine comprises at least one electronic control unit (ECU) located close to the engine and normally housed in the engine compartment of a vehicle; and a number of sensors connected to the control unit to measure various power train operating parameters (e.g. drive shaft angular position and rotation speed) which are used by the control unit to control the power train.
Optimum control of power train performance by the control system calls for measuring various power train parameters which are extremely complicated and expensive to measure (such as the rotation speed of a turbosupercharger). In other words, certain power train parameters (such as turbosupercharger rotation speed) can only be measured accurately using either laboratory instruments (which are extremely accurate but obviously unfeasible in a mass production context, for reasons of cost, size, and dependability) or invasive, extremely high-cost, potentially unreliable sensors.
US 20010023685 A1 discloses an air-fuel mixture control device controlling a combustible air-fuel mixture to be supplied to a combustion chamber of an engine; this device is constructed of an injector used for fuel supply, a fuel pump, a fuel filter, a fuel pressure regulator, and an electronic control unit, which are united as an assembly with respect to a throttle body including an intake passage and a throttle valve. A memory incorporated in the ECU stores a correction value with respect to the fuel injection quantity dispersion preliminarily experimentally determined on an assembly-by-assembly basis; the ECU corrects the fuel injection quantity based on the correction value stored in the memory to control the fuel injection quantity.